feat: Add KoikatsuBlenderPipeline addon with import/export functionality

- Add core addon files (__init__.py, KKPanel.py, preferences.py, common.py)
- Add import pipeline with armature, mesh, and material modification modules
- Add export pipeline with material baking and FBX preparation utilities
- Add material combiner tool for texture atlas generation and optimization
- Add extras utilities for animation, rigging, and asset management
- Add bone orientation data from better_fbx for accurate skeletal structure
- Add comprehensive documentation and wiki with multi-language support (EN, JP, ZH)
- Add animation library retargeting lists for ARP and Rokoko motion capture
- Add Rigify integration scripts for advanced rigging workflows
- Add shader file (KK Shader V8.0.blend) for material rendering
- Add manifest and license files for addon distribution
- Add changelog documenting version history and improvements
- Initialize complete Blender addon project for Koikatsu character import/export

exporting/material_combiner/textures.py

@@ -0,0 +1,13 @@
+from typing import Dict
+
+import bpy
+
+
+def get_texture(mat: bpy.types.Material) -> bpy.types.Texture:
+    return next((slot.texture for idx, slot in enumerate(mat.texture_slots) if
+                 slot is not None and mat.use_textures[idx]), None)
+
+
+def get_textures(mat: bpy.types.Material) -> Dict[int, bpy.types.Texture]:
+    return {idx: slot.texture for idx, slot in enumerate(mat.texture_slots) if
+            slot is not None and mat.use_textures[idx]}